__pip-runner__.py

"""Execute exactly this copy of pip, within a different environment.

This file is named as it is, to ensure that this module can't be imported via
an import statement.
"""

# /!\ This version compatibility check section must be Python 2 compatible. /!\

import sys

# Copied from pyproject.toml
PYTHON_REQUIRES = (3, 8)


def version_str(version):  # type: ignore
    return ".".join(str(v) for v in version)


if sys.version_info[:2] < PYTHON_REQUIRES:
    raise SystemExit(
        "This version of pip does not support python {} (requires >={}).".format(
            version_str(sys.version_info[:2]), version_str(PYTHON_REQUIRES)
        )
    )

# From here on, we can use Python 3 features, but the syntax must remain
# Python 2 compatible.

import runpy  # noqa: E402
from importlib.machinery import PathFinder  # noqa: E402
from os.path import dirname  # noqa: E402

PIP_SOURCES_ROOT = dirname(dirname(__file__))


class PipImportRedirectingFinder:
    @classmethod
    def find_spec(self, fullname, path=None, target=None):  # type: ignore
        if fullname != "pip":
            return None

        spec = PathFinder.find_spec(fullname, [PIP_SOURCES_ROOT], target)
        assert spec, (PIP_SOURCES_ROOT, fullname)
        return spec


sys.meta_path.insert(0, PipImportRedirectingFinder())

assert __name__ == "__main__", "Cannot run __pip-runner__.py as a non-main module"
runpy.run_module("pip", run_name="__main__", alter_sys=True)